#!/bin/bash

# PostgreSQL startup script for Slackware Linux
#
# $Revision$
# $Date$
#
# Copyright 2007-2018 Adis Nezirovic <adis_at_linux.org.ba>
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# Do not source this script (since it contains exit() calls)
#
# Since version 9.3 this startup script can run multiple PostgreSQL
# versions on different ports and with different data dirs.
# 
# e.g. PG_VERSION=14 PG_PORT=6432 /etc/rc.d/rc.@PRGNAM@ start

PG_VERSION=${PG_VERSION:-@PG_VERSION@}
PG_PORT=${PG_PORT:-@PG_PORT@}
LIBDIRSUFFIX="@LIBDIRSUFFIX@"
LOGFILE=/var/log/@PRGNAM@-$PG_VERSION
DATADIR=/var/lib/pgsql/$PG_VERSION/data
POSTGRES=/usr/lib${LIBDIRSUFFIX}/@PRGNAM@/$PG_VERSION/bin/postgres
PG_CTL=/usr/lib${LIBDIRSUFFIX}/@PRGNAM@/$PG_VERSION/bin/pg_ctl
PIDFILE=$DATADIR/postmaster.pid

# oom-killer score
#
# https://www.postgresql.org/docs/14/kernel-resources.html#LINUX-MEMORY-OVERCOMMIT
PG_OOM_ADJUST_FILE=/proc/self/oom_score_adj
PG_MASTER_OOM_SCORE_ADJ=-1000
PG_CHILD_OOM_SCORE_ADJ=0
PG_ENV="PG_OOM_ADJUST_FILE=$PG_OOM_ADJUST_FILE PG_OOM_ADJUST_VALUE=$PG_CHILD_OOM_SCORE_ADJ"

# Return values (according to LSB):
# 0 - success
# 1 - generic or unspecified error
# 2 - invalid or excess argument(s)
# 3 - unimplemented feature (e.g. "reload")
# 4 - insufficient privilege
# 5 - program is not installed
# 6 - program is not configured
# 7 - program is not running

pg_ctl()
{
	CMD="$PG_CTL -o '-p $PG_PORT' $@"
	su - postgres -c "$PG_ENV $CMD"
}

if [ ! -f $POSTGRES ]; then
	echo "Could not find 'postgres' binary. Maybe PostgreSQL is not installed properly?"
	exit 5
fi

case "$1" in

	"start")
		echo "Starting PostgreSQL"
		touch $LOGFILE
		chown postgres:wheel $LOGFILE
		chmod 0640 $LOGFILE
	
		if [ ! -e $DATADIR/PG_VERSION ]; then
			echo "You should initialize the PostgreSQL database at location $DATADIR"
			echo "e.g. su postgres -c \"initdb -D $DATADIR --locale=en_US.UTF-8 -A md5 -W\""
			exit 6
		fi
	
		if [ $(pgrep -f $POSTGRES) ]; then

			echo "PostgreSQL daemon already running"
			if [ ! -f $PIDFILE ]; then
				echo "Warning: Missing pid file $PIDFILE"
			fi
			exit 1

		else
			test -e "$PG_OOM_ADJUST_FILE" && echo "$PG_MASTER_OOM_SCORE_ADJ" > "$PG_OOM_ADJUST_FILE"
			pg_ctl start -w -l $LOGFILE -D $DATADIR
			exit 0
		fi	
	;;

	"stop")
		echo "Shutting down PostgreSQL..."
		pg_ctl stop -l $LOGFILE -D $DATADIR -m smart
	;;

	"force-stop")
		# Take care! This will kill _all_ client connections
		# and rollback current transactions.
		echo "Shutting down PostgreSQL (fast)..."
		pg_ctl stop -l $LOGFILE -D $DATADIR -m fast
	;;
	
	"unclean-stop")
		# Take care! This will abort server process itself
		# resulting with database recovery on next start.
		echo "Shutting down PostgreSQL (immediate)..."
		pg_ctl stop -l $LOGFILE -D $DATADIR -m immediate
	;;

	"restart")
		echo "Restarting PostgreSQL..."
		test -e "$PG_OOM_ADJUST_FILE" && echo "$PG_MASTER_OOM_SCORE_ADJ" > "$PG_OOM_ADJUST_FILE"
		pg_ctl restart -l $LOGFILE -D $DATADIR -m smart
	;;

	"force-restart")
		# Take care! This will kill _all_ client connections
		# and rollback current transactions.
		echo "Restarting PostgreSQL (fast)..."
		pg_ctl restart -l $LOGFILE -D $DATADIR -m fast
	;;

	"unclean-restart")
		# Take care: This will abort server process itself
		# resulting with database recovery on start.
		echo "Restarting PostgreSQL (immediate)..."
		pg_ctl restart -l $LOGFILE -D $DATADIR -m immediate
	;;

	"reload")
		echo "Reloading configuration for PostgreSQL..."
		pg_ctl reload -l $LOGFILE -D $DATADIR -m smart
	;;

	"status")
		if [ $(pgrep -f $POSTGRES) ]; then
			echo "PostgreSQL is running"

			if [ ! -e $PIDFILE ]; then
				echo "Warning: Missing pid file $PIDFILE"
			fi

			exit 0
		else
			echo "PostgreSQL is stopped"

			if [ -e $PIDFILE ]; then
				echo "Detected stale pid file $PIDFILE"
			fi

			exit 0
		fi
	;;

	*)
		# unclean-stop and unclean-restart are not documented on purpose.
		echo "Usage: $0 {start|stop|force-stop|status|restart|force-restart|reload}"
		exit 1
	;;
esac	
